How does the diff work?

It uses jsdiff, an implementation of the Myers diff algorithm, which finds the smallest set of added and removed lines that turns the original into the changed version. git diff is based on the same algorithm.

Can I compare JSON files?

Yes, as text. For a meaningful result, format both with the same indentation first (the JSON formatter does this), so differences in whitespace don't hide the real changes.

Is my code or data uploaded anywhere?

No. Every tool runs in your browser, so your code, tokens, keys and files are processed on your device and are not sent to our server or stored. Reloading or closing the page clears them.

Yes. Every tool is free with no sign-up and no limits on use. Clearly labeled ads keep it that way.

Does it work on my phone?

Yes. The tools work in any modern browser on phones, tablets and computers, though large files and long code are easier to handle on a computer.

Diff Checker

Compare two versions and see exactly what changed.

100% Free
No Sign Up
Works in Your Browser

Diff checker

Compare two texts or code files

Original text

Changed text

View

Highlight

Whitespace

Ignore caseFold unchanged lines

−4 removals+5 additions3 unchanged

1−function greet(name) {

1+function greet(name, greeting = "Hello") {

2− console.log("Hello, " + name);

2+ console.log(`${greeting}, ${name}!`);

3 return true;

6−const users = ["Ada", "Alan", "Grace"];

6+const users = ["Ada", "Alan", "Grace", "Margaret"];

7−users.forEach(greet);

7+users.forEach((u) => greet(u));

8+// Done

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How to use the diff checker

Three steps, all in your browser.

1
Paste both versions
Put the original on one side and the changed version on the other.
2
Read the result
Matches, differences or the explanation update as you type.
3
Copy the result
Copy the output in one click. Nothing is saved or sent anywhere.

Diff Checker: what to know

The diff checker compares two versions of a text or code file and highlights what changed: removed lines in red, added lines in green. It uses jsdiff, an open-source implementation of the Myers diff algorithm, the same approach git diff uses, which finds the smallest set of changes that turns the original into the new version.

Paste the original on one side and the changed version on the other. Lines that were edited rather than added or removed are paired up, with the changed words highlighted inside them, and options can ignore differences in whitespace or letter case. It works for anything that's text: source code, config files, SQL, JSON, logs or translations. Both texts stay in your browser, which matters when you're comparing code or documents you can't share.

Whitespace and formatting differences show up as changes too. When comparing JSON, XML or code that was formatted differently, run both through the same formatter first so the diff shows only the changes that matter.

Popular uses

Comparing two versions of a config file
Checking what changed in a document or contract
Reviewing code changes outside of Git
Comparing API responses before and after a change

Tips for the best result

Format JSON on both sides first with the JSON formatter for a clean comparison.
Line ending differences (Windows CRLF vs Unix LF) can make every line look changed.
For very long files, compare the section you care about.

Read how JustYourDev works and our privacy details. Code, data and files you use here are processed in your browser and are never sent to our server.

More Developer Tools

Every everyday developer tool, right in your browser.

How to use the diff checker

Paste both versions

Read the result

Copy the result